We present a measurement of the branching fraction and time-dependent charge-parity (CP) decay-rate asymmetries in B0→J/ψπ0 decays. The data sample was collected with the Belle II detector at the SuperKEKB asymmetric e+e- collider in 2019-2022 and contains (387±6)×106 BB¯ meson pairs from ϒ(4S) decays. We reconstruct 392±24 signal decays and fit the CP parameters from the distribution of the proper-decay-time difference of the two B mesons. We measure the branching fraction to be (B0→J/ψπ0)=(2.00±0.12±0.09)×10-5 and the direct and mixing-induced CP asymmetries to be CCP=0.13±0.12±0.03 and SCP=-0.88±0.17±0.03, respectively, where the first uncertainties are statistical and the second are systematic. We observe mixing-induced CP violation with a significance of 5.0 standard deviations for the first time in this mode.

Observation of time-dependent CP violation and measurement of the branching fraction of B0 →j/ψπ0 decays / Belle, C., Adachi, I., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., Aloisio, A., Althubiti, N., Anh Ky, N., Asner, D. m., Atmacan, H., Aushev, V., Aversano, M., Ayad, R., Babu, V., Bae, H., Baghel, N. k., Bahinipati, S., Bambade, P., Banerjee, Sw., et al.. - In: PHYSICAL REVIEW D. - ISSN 2470-0010. - 111:1(2025), pp. 012011.1-012011.12. [10.1103/physrevd.111.012011]

Observation of time-dependent CP violation and measurement of the branching fraction of B0 →j/ψπ0 decays

Dorigo, M.;Gabrielli, A.;Ganiev, E.;Gaudino, G.;Ghosh, D.;Giordano, R.;Gobbo, B.;Graziani, E.;Johnson, A.;Kumar, R.;Li, Y.;Mancinelli, G.;Manfredi, R.;Mantovano, M.;Martini, A.;Merola, M.;Park, H.;Park, J.;Park, K.;Raiz, S.;Serrano, J.;Soffer, A.;Veronesi, M.;Vitale, L.;
2025-01-01

Abstract

We present a measurement of the branching fraction and time-dependent charge-parity (CP) decay-rate asymmetries in B0→J/ψπ0 decays. The data sample was collected with the Belle II detector at the SuperKEKB asymmetric e+e- collider in 2019-2022 and contains (387±6)×106 BB¯ meson pairs from ϒ(4S) decays. We reconstruct 392±24 signal decays and fit the CP parameters from the distribution of the proper-decay-time difference of the two B mesons. We measure the branching fraction to be (B0→J/ψπ0)=(2.00±0.12±0.09)×10-5 and the direct and mixing-induced CP asymmetries to be CCP=0.13±0.12±0.03 and SCP=-0.88±0.17±0.03, respectively, where the first uncertainties are statistical and the second are systematic. We observe mixing-induced CP violation with a significance of 5.0 standard deviations for the first time in this mode.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3121655
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